This invention relates in general to power take-offs for providing rotational energy from a source of rotational energy to a driven accessory. In particular, this invention relates to a combined power take-off and synchronized clutch assembly (referred to herein more simply as a synchronizer assembly for selectively connecting the source of rotational energy to the driven accessory.
A power take-off is a well known mechanical device that is often used in conjunction with a source of rotational energy, such as a vehicle engine or transmission, to provide rotational energy to a driven accessory, such as a hydraulic pump that is supported on the vehicle. For example, power take-offs are commonly used on industrial and agricultural vehicles to provide rotational energy to hydraulic pumps that, in turn, are used to operate hydraulically driven accessories such as plows, trash compactors, lifting mechanisms, winches, and the like. The power take-off provides a simple, inexpensive, and convenient means for supplying energy from the source of rotational energy to the hydraulic pump that, in turn, provides relatively high pressure fluid to operate the driven accessory.
A typical power take-off includes an input mechanism and an output mechanism. The input mechanism of the power take-off is adapted to be connected to the source of rotational energy so as to be rotatably driven whenever the source of rotational energy is operated. The output mechanism of the power take-off is adapted to be connected to the rotatably driven accessory. In some instances, the input mechanism of the power take-off is directly connected to the output mechanism such that the driven accessory is rotatably driven whenever the source of rotational energy is operated. In other instances, a clutch assembly is provided between the input mechanism and the output mechanism such that the driven accessory is rotatably driven only when the clutch assembly is engaged while the source of rotational energy is operated.
The structures of the clutch assemblies that are typically provided in conventional power take-offs can be classified in two general categories. The first category is often referred to as a manual shift clutch assembly, which uses a sliding gear or similar splined coupling to selectively connect the input mechanism of the power take-off to the output mechanism. Manual shift clutch assemblies are relatively simple and inexpensive, but are prone to damage if operated improperly. The second category is often referred to as a hot shift clutch assembly, which uses plurality of friction discs to selectively connect the input mechanism of the power take-off to the output mechanism. Hot shift clutch assemblies are less prone to damage, but are relatively complicated and expensive. Thus, it would be desirable to provide an improved structure for a power take-off that is relatively simple, inexpensive, and not prone to damage.